Messages in this thread Patch in this message | | | Date | Sun, 29 Oct 2006 21:58:26 +0300 | From | Oleg Nesterov <> | Subject | [PATCH] xacct_add_tsk: fix pure theoretical ->mm use-after-free |
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Paranoid fix. The task can free its ->mm after the 'if (p->mm)' check.
Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
--- STATS/kernel/tsacct.c~3_mm 2006-10-27 01:03:26.000000000 +0400 +++ STATS/kernel/tsacct.c 2006-10-29 21:46:12.000000000 +0300 @@ -80,13 +80,17 @@ void bacct_add_tsk(struct taskstats *sta */ void xacct_add_tsk(struct taskstats *stats, struct task_struct *p) { + struct mm_struct *mm; + /* convert pages-jiffies to Mbyte-usec */ stats->coremem = jiffies_to_usecs(p->acct_rss_mem1) * PAGE_SIZE / MB; stats->virtmem = jiffies_to_usecs(p->acct_vm_mem1) * PAGE_SIZE / MB; - if (p->mm) { + mm = get_task_mm(p); + if (mm) { /* adjust to KB unit */ - stats->hiwater_rss = p->mm->hiwater_rss * PAGE_SIZE / KB; - stats->hiwater_vm = p->mm->hiwater_vm * PAGE_SIZE / KB; + stats->hiwater_rss = mm->hiwater_rss * PAGE_SIZE / KB; + stats->hiwater_vm = mm->hiwater_vm * PAGE_SIZE / KB; + mmput(mm); } stats->read_char = p->rchar; stats->write_char = p->wchar; - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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